A quick way to determine if a method exists is to look in the API Help. For example, I opened up the local API Help, went to the Index tab, typed in "bend line", and quickly found IView::ShowSheetMetalBendNotes. If you are new to the API, you can see more examples on how to use the API Help in Lesson 2.2, a free tutorial at my web site.

Here is some code that will toggle the bend line note state of Drawing View1: